[Phanx]

Re: Grouping bars

Just handle it like any other variable-length collection of objects or values.

Creating a bar group:

local barGroup = CreateFrame("Frame", nil, UIParent)
-- add title bar, backdrop, etc. here
barGroup.bars = {}

Adding a bar to the group:

local bar = LibStub("LibCandyBar-3.0"):New(texture, 100, 16)
bar:SetDuration(90)
bar:SetLabel("Something")
bar:Start()

bar:SetParent(barGroup)
table.insert(barGroup.bars, bar)
MyAddon:ArrangeBars()

function MyAddon:ArrangeBars()
    for i = 1, #barGroup.bars do
        local bar = barGroup.bars[i]
        bar:SetPoint("LEFT", 1, 0)
        bar:SetPoint("RIGHT", -1, 0)
        if i > 1 then
            bar:SetPoint("TOP", barGroup.bars[i - 1], "BOTTOM", 0, -1)
        else
            bar:SetPoint("TOP", barGroup, 0, -1)
        end
    end
end

Removing references to the bar when it ends:

LibStub("LibCandyBar-3.0"):RegisterCallback(MyAddon, "LibCandyBar_Stop")

function MyAddon:LibCandyBar_Stop(_, bar)
    for i = 1, #barGroup.bars do
        if barGroup.bars[i] == bar then
            table.remove(barGroup.bars, i)
            break
        end
    end
    self:ArrangeBars()
end

Please note that I have never used LibCandyBar-3.0, so all of the above is based on a quick reading of the API documentation you linked, and a few assumptions since that documentation is somewhat lacking.

Re: Animation

What are you trying to animate? Any half-decent timer bar library should already handle animating the bar to show time elapsed/remaining. The animations you see on Blizzard bars like your health bar would not make sense on a timer bar, since the value of a timer bar changes very frequently in very small increments -- there are no sudden large changes you want to smooth out or call attention to (eg. by flashing).

Re: Sorting

Just sort the table that contains a list of active bars before you position them:

local function sortBarsByRemainingTime(a, b)
    return a.remaining < b.remaining
end

function MyAddon:ArrangeBars()
    table.sort(barGroup.bars, sortBarsByRemainingTime)
    for i = 1, #barGroup.bars do